Editing Nitrogen (section)

===Atomic===
[[File:Neon orbitals.png|thumb|upright=1.6|right|The shapes of the five orbitals occupied in nitrogen. The two colours show the phase or sign of the wave function in each region. From left to right: 1s, 2s (cutaway to show internal structure), 2p<sub>''x''</sub>, 2p<sub>''y''</sub>, 2p<sub>''z''</sub>.]]
A nitrogen atom has seven electrons. In the ground state, they are arranged in the electron configuration 1s{{su|p=2}}2s{{su|p=2}}2p{{su|p=1|b=''x''}}2p{{su|p=1|b=''y''}}2p{{su|p=1|b=''z''}}. It, therefore, has five [[valence electron]]s in the 2s and 2p orbitals, three of which (the p-electrons) are unpaired. It has one of the highest [[electronegativity|electronegativities]] among the elements (3.04 on the Pauling scale), exceeded only by [[chlorine]] (3.16), [[oxygen]] (3.44), and [[fluorine]] (3.98). (The light [[noble gas]]es, [[helium]], [[neon]], and [[argon]], would presumably also be more electronegative, and in fact are on the Allen scale.)<ref name="Greenwood411" /> Following periodic trends, its single-bond [[covalent radius]] of 71&nbsp;pm is smaller than those of [[boron]] (84&nbsp;pm) and [[carbon]] (76&nbsp;pm), while it is larger than those of oxygen (66&nbsp;pm) and fluorine (57&nbsp;pm). The [[nitride]] anion, N<sup>3−</sup>, is much larger at 146&nbsp;pm, similar to that of the [[oxide]] (O<sup>2−</sup>: 140&nbsp;pm) and [[fluoride]] (F<sup>−</sup>: 133&nbsp;pm) anions.<ref name="Greenwood411" /> The first three ionisation energies of nitrogen are 1.402, 2.856, and 4.577&nbsp;MJ·mol<sup>−1</sup>, and the sum of the fourth and fifth is {{val|16.920|u=MJ·mol<sup>−1</sup>}}. Due to these very high figures, nitrogen has no simple cationic chemistry.<ref name="Greenwood550">Greenwood and Earnshaw, p. 550</ref>
The lack of radial nodes in the 2p subshell is directly responsible for many of the anomalous properties of the first row of the [[p-block]], especially in nitrogen, oxygen, and fluorine. The 2p subshell is very small and has a very similar radius to the 2s shell, facilitating [[orbital hybridisation]]. It also results in very large electrostatic forces of attraction between the nucleus and the valence electrons in the 2s and 2p shells, resulting in very high electronegativities. [[Hypervalent molecule|Hypervalency]] is almost unknown in the 2p elements for the same reason, because the high electronegativity makes it difficult for a small nitrogen atom to be a central atom in an electron-rich [[three-center four-electron bond]] since it would tend to attract the electrons strongly to itself. Thus, despite nitrogen's position at the head of group 15 in the periodic table, its chemistry shows huge differences from that of its heavier congeners [[phosphorus]], [[arsenic]], [[antimony]], and [[bismuth]].<ref name="Kaupp">{{cite journal |last=Kaupp |first=Martin |date=1 December 2006 |title=The role of radial nodes of atomic orbitals for chemical bonding and the periodic table |journal=Journal of Computational Chemistry |volume=28 |issue=1 |pages=320–25 |doi=10.1002/jcc.20522 |pmid=17143872 |s2cid=12677737 |doi-access=free }}</ref>

Nitrogen may be usefully compared to its horizontal neighbours' carbon and oxygen as well as its vertical neighbours in the pnictogen column, phosphorus, arsenic, antimony, and bismuth. Although each period 2 element from lithium to oxygen shows some similarities to the period 3 element in the next group (from magnesium to chlorine; these are known as [[diagonal relationship]]s), their degree drops off abruptly past the boron–silicon pair. The similarities of nitrogen to sulfur are mostly limited to sulfur nitride ring compounds when both elements are the only ones present.<ref name="Greenwood412" />

Nitrogen does not share the proclivity of carbon for [[catenation]]. Like carbon, nitrogen tends to form ionic or metallic compounds with metals. Nitrogen forms an extensive series of nitrides with carbon, including those with chain-, [[graphite|graphitic-]], and [[fullerene|fullerenic]]-like structures.<ref>{{cite journal |last1=Miller |first1=T. S. |last2=Belen |first2= A.|last3= Suter|first3= T. M.|last4= Sella|first4= A.|last5= Corà|first5= A.|last6= McMillan|first6= P. F.|date=2017 |title= Carbon nitrides: synthesis and characterization of a new class of functional materials |journal=Physical Chemistry Chemical Physics |volume= 19|issue= 24|pages=15613–15638 |doi=10.1039/C7CP02711G|pmid=28594419 |bibcode=2017PCCP...1915613M |doi-access= free}}</ref>

It resembles oxygen with its high electronegativity and concomitant capability for [[hydrogen bond]]ing and the ability to form [[coordination complex]]es by donating its [[lone pair]]s of electrons. There are some parallels between the chemistry of ammonia NH<sub>3</sub> and water H<sub>2</sub>O. For example, the capacity of both compounds to be protonated to give NH<sub>4</sub><sup>+</sup> and H<sub>3</sub>O<sup>+</sup> or deprotonated to give NH<sub>2</sub><sup>−</sup> and OH<sup>−</sup>, with all of these able to be isolated in solid compounds.<ref>{{cite book |last1= House|first1=J. E. |last2=House |first2= K. A.|date=2016 |title=Descriptive Inorganic Chemistry |location= Amsterdam|publisher= Elsevier|page= 198|isbn=978-0-12-804697-5 }}</ref>

Nitrogen shares with both its horizontal neighbours a preference for forming multiple bonds, typically with carbon, oxygen, or other nitrogen atoms, through p<sub>''π''</sub>–p<sub>''π''</sub> interactions.<ref name="Greenwood412" /> Thus, for example, nitrogen occurs as diatomic molecules and therefore has very much lower [[melting point|melting]] (−210&nbsp;°C) and [[boiling point]]s (−196&nbsp;°C) than the rest of its group, as the N<sub>2</sub> molecules are only held together by weak [[van der Waals interaction]]s and there are very few electrons available to create significant instantaneous dipoles. This is not possible for its vertical neighbours; thus, the [[nitrogen oxide]]s, [[nitrite]]s, [[nitrate]]s, [[nitro compound|nitro-]], [[nitroso]]-, [[azo compound|azo]]-, and [[diazo]]-compounds, [[azide]]s, [[cyanate]]s, [[thiocyanate]]s, and [[imino]]-derivatives find no echo with phosphorus, arsenic, antimony, or bismuth. By the same token, however, the complexity of the phosphorus oxoacids finds no echo with nitrogen.<ref name="Greenwood412" /> Setting aside their differences, nitrogen and phosphorus form an extensive series of compounds with one another; these have chain, ring, and cage structures.<ref>{{cite book |last1=Roy  |first1= A. K.|last2=Burns  |first2= G. T.|last3=Grigora  |first3= S.|last4=Lie  |first4= G. C.|editor-last1= Wisian-Neilson|editor-first1= P.|editor-last2= Alcock|editor-first2= H. R.|editor-last3= Wynne|editor-first3= K. J.|title=Inorganic and organometallic polymers II: advanced materials and intermediates |publisher=American Chemical Society |date=1994 |pages=344–357 |chapter=Poly(alkyl/aryloxothiazenes), [N=S(O)R]''<sub>n</sub>'' : New direction in inorganic polymers |doi=10.1021/bk-1994-0572.ch026}}</ref>

Table of thermal and physical properties of nitrogen (N<sub>2</sub>) at atmospheric pressure:<ref>{{Cite book |last=Holman |first=Jack P. |url=https://www.worldcat.org/oclc/46959719 |title=Heat transfer |publisher=McGraw-Hill Companies, Inc. |year=2002 |isbn=9780072406559 |edition=9th |location=New York, NY |pages=600–606 |language=English |oclc=46959719}}</ref><ref>{{Cite book |last1=Incropera |last2=Dewitt |last3=Bergman |last4=Lavigne |first1=Frank P. |first2=David P. |first3=Theodore L. |first4=Adrienne S. |url=https://www.worldcat.org/oclc/62532755 |title=Fundamentals of heat and mass transfer. |publisher=John Wiley and Sons, Inc. |year=2007 |isbn=9780471457282 |edition=6th |location=Hoboken, NJ |pages=941–950 |language=English |oclc=62532755}}</ref>
{|class="wikitable mw-collapsible mw-collapsed", style="text-align: right"
|style="text-align: center"|Temperature (K)
|style="text-align: center"|Density (kg&nbsp;m<sup>−3</sup>)
|style="text-align: center"|Specific heat (kJ&nbsp;kg<sup>−1</sup>&nbsp;°C<sup>−1</sup>)
|style="text-align: center"|Dynamic viscosity (kg&nbsp;m<sup>−1</sup>&nbsp;s<sup>−1</sup>)
|style="text-align: center"|Kinematic viscosity (m<sup>2</sup>&nbsp;s<sup>−1</sup>)
|style="text-align: center"|Thermal conductivity (W&nbsp;m<sup>−1</sup>&nbsp;°C<sup>−1</sup>)
|style="text-align: center"|Thermal diffusivity (m<sup>2</sup>&nbsp;s<sup>−1</sup>)
|style="text-align: center"|[[Prandtl number]]
|-
|100
|3.4388
|1.07{{figure space}}{{figure space}}
|{{val|6.88e-6}}
|{{val|2.00e-6}}
|{{gaps|0.009|58}}
|{{val|2.60e-6}}
|0.768
|-
|150
|2.2594
|1.05{{figure space}}{{figure space}}
|{{val|1.01e-5}}
|{{val|4.45e-6}}
|{{gaps|0.013|9{{figure space}}}}
|{{val|5.86e-6}}
|0.759
|-
|200
|1.7108
|1.0429
|{{val|1.29e-5}}
|{{val|7.57e-6}}
|{{gaps|0.018|24}}
|{{val|1.02e-5}}
|0.747
|-
|300
|1.1421
|1.0408
|{{val|1.78e-5}}
|{{val|1.56e-5}}
|{{gaps|0.026|2{{figure space}}}}
|{{val|2.20e-5}}
|0.713
|-
|400
|0.8538
|1.0459
|{{val|2.20e-5}}
|{{val|2.57e-5}}
|{{gaps|0.033|35}}
|{{val|3.73e-5}}
|0.691
|-
|500
|0.6824
|1.0555
|{{val|2.57e-5}}
|{{val|3.77e-5}}
|{{gaps|0.039|84}}
|{{val|5.53e-5}}
|0.684
|-
|600
|0.5687
|1.0756
|{{val|2.91e-5}}
|{{val|5.12e-5}}
|{{gaps|0.045|8{{figure space}}}}
|{{val|7.49e-5}}
|0.686
|-
|700
|0.4934
|1.0969
|{{val|3.21e-5}}
|{{val|6.67e-5}}
|{{gaps|0.051|23}}
|{{val|9.47e-5}}
|0.691
|-
|800
|0.4277
|1.1225
|{{val|3.48e-5}}
|{{val|8.15e-5}}
|{{gaps|0.056|09}}
|{{val|1.17e-4}}
|0.7{{figure space}}{{figure space}}
|-
|900
|0.3796
|1.1464
|{{val|3.75e-5}}
|{{val|9.11e-5}}
|{{gaps|0.060|7{{figure space}}}}
|{{val|1.39e-4}}
|0.711
|-
|1000
|0.3412
|1.1677
|{{val|4.00e-5}}
|{{val|1.19e-4}}
|{{gaps|0.064|75}}
|{{val|1.63e-4}}
|0.724
|-
|1100
|0.3108
|1.1857
|{{val|4.23e-5}}
|{{val|1.36e-4}}
|{{gaps|0.068|5{{figure space}}}}
|{{val|1.86e-4}}
|0.736
|-
|1200
|0.2851
|1.2037
|{{val|4.45e-5}}
|{{val|1.56e-4}}
|{{gaps|0.071|84}}
|{{val|2.09e-4}}
|0.748
|-
|{{val|1300}}
|0.2591
|1.219{{figure space}}
|{{val|4.66e-5}}
|{{val|1.80e-4}}
|{{gaps|0.081|{{figure space}}{{figure space}}}}
|{{val|2.56e-4}}
|0.701
|}